Physics Review for the GHSGT

Speed Measure of how quickly an object gets from one place to another

Speed, distance and time

Speed and velocity v=d/t Steeper the line, greater the speed Distance vs. Time

Acceleration Rate of change in speed per time Example Driver of a car hitting the gas and traveling faster 35 mi/hr/sec Driver of a car hitting the brakes -20 mi/hr/sec (negative acceleration)

a=200-0/0.8 a=250 m/s 2

Momentum The more momentum an object has, the more difficult it is to STOP! Momentum Velocity Mass

Force A push or pull Free Body Diagram Shows forces acting on an object Balanced forces shown 6 N

Unbalanced Forces Unbalanced forces shown Opposite directions so subtract to calculate net force Same direction, add to calculate net force 2 N 6 N

Friction and air resistance The force between 2 objects in contact that opposes the motion of either object Types of friction Rolling Sliding Air Viscous (fluids)

Gravity The attraction Gravitational force between to objects is proportional to the product of their masses. The farther away the objects are, the smaller the gravitational force.

Newton’s First Law An object at rest remains at rest and an object in motion maintains its velocity unless it experiences an unbalanced force. Examples: Objects moving at a constant speed or not moving at all

A force will cause a mass to accelerate!

Gravity

Weight vs. Mass w=mg F=ma Remember the similarity between these two formulas. Weight is your mass times acceleration due to gravity 9.8 m/s/s on Earth

Work W=Fd Unit of measurement – Joule (J) Same unit of measurement as Energy!

Work: components of force must be parallel to displacement Picking up suitcase Carrying the suitcase

Types of energy Solar Electrical Nuclear Chemical Mechanical Potential Kinetic

Conservation of mechanical energy In the absence of friction, the total mechanical energy remains constant

Temperature scales Fahrenheit English system Water freezes - 32° Water boils - 212° Room temp - 68° Celsius (centigrade) Metric system Water freezes – 0° Water boils – 100° Room temp – 20° Kelvin Celsius + 273

Converting Celsius and Fahrenheit

Thermal energy Not the same as temperature! Temperature measures the average kinetic energy of the molecules. Thermal energy is the sum of all the kinetic and potential energies of the molecules of the substance. Amount of thermal energy stored depends on 3 things: Mass, temperature and amount of energy stored per degree

Heat Transfer

Insulator or conductor? Materials that conduct heat easily are: Thermal conductors Materials that conduct heat poorly are: Thermal insulators

Heat equation Q = mcΔT Heat energy mass Specific heat Change in temperature  Amount of thermal energy stored depends on 3 things: Mass, temperature and amount of energy stored per degree

Parts of a transverse wave

Longitudinal (compressional) Waves

Waves

Frequency and wavelength Frequency = cycles/ time Wavelength = length of wave A – Longest wavelength C – greatest frequency and energy A CB v=fλ

Wave behavior

Constructive and destructive interference

How sound travels

Doppler Effect As a rapidly moving object approaches you, you hear a higher pitch because of the compressed sound waves causing a higher frequency. As the object speeds away from you the sound waves stretch out and you hear a lower pitch because of the lower frequency.

Refraction, Diffraction and Reflection

Convex and Concave Lenses

Static electricity and Moving Electricity (Current)

Ohm’s Law

Electrical circuit diagrams

Magnetism